Geometrical instrument



FIG. 1 is a top and right front perspective view of a geometrical instrument showing my new design;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a cross-sectional view as taken from line 3--3 of FIG. 1;

FIG. 4 is a bottom plan view thereof. 

The ornamental design for a geometrical instrument, as shown. 